1. Field
The invention relates to the intervertebral spinal implant, which finds application in surgical spinal treatment in order to maintain proper distance between adjacent vertebrae and stabilization of treated spinal segment.
2. Discussion of Prior Art
From the patent application US 2010/0049325 an intervertebral implant is known, which consists of two parts, which are introduced between two vertebrae. A first part has a first contact surface extending between its two ends a first guide surface extending out from the first contact surface. A second part has a second contact surface extending between its ends, and a second guide surface recessed into the second contact surface. The first guide surface and the second guide surface cooperate so that the first contact surface of the first part can slide relative to the second contact surface of the second part with a translation motion guided by the cooperating structures of the first and second guide surfaces. The height of the intervertebral implant can be altered by shifting the first part and the second part relative to each other by moving the contact surfaces relative to each other by using the cooperating guide surfaces. The inconvenience of this solution is small overall surface of holes allowing for a bony overgrowth, possibility of not intended change of the implant's height as a result of the shifting of two parts relative to each other and a lack of means, which prevent sliding the implant off the intervertebral space.
From the patent application US 2009/0157186 an intervertebral implant is known, which comprises a first part and a second part, which may be uniportally implanted in a disc cavity and connected to each other therein. The parts comprise an opening for housing spongiosa or bone replacement material. Both parts have connector means, which engage with each other on implantation in the disc cavity and thus connect both parts to each other. At least one part preferably comprises a groove in which a spring of the other part may be introduced in a sliding manner. The groove and the spring are arranged on the inner narrow faces of both parts which are to come together. The implant may be implanted uniportally through a transforaminal or an extraforaminal opening. The inconvenience of this solution is a very small bearing surface of the implant, which causes great pressure of the implant on the bone, and penetration of the implant into the bone. Both implant's parts are wide, which requires relatively big surgical approach. The implant doesn't comprise means, which prevent shifting of the implant and sliding the implant off the intervertebral space.
From the patent application WO 2010/045231 intervertebral spacer is known, which comprises implant installed between adjacent vertebral bodies. The implant is provided with support body and a rotatable insert. The support body can be curved or has a shape of an arch extending in lateral direction between proximal and distal frontal part of the implant. Distal frontal part of the implant can have a conical end. Proximal frontal part is provided with a hole, in which is situated element for cooperation with installation tool. In one embodiment the implant is provided with a hole which allows for bony overgrowth through the implant and bony fusion after implantation. Opposite surfaces of the implant are provided with projections or teeth preventing sliding the implant off the intervertebral space. The inconvenience of this solution is very small bearing surface of the implant, which causes great pressure of the implant on the bone, and penetration of the implant into the bone. Because of a location of the overgrowth hole on lateral walls of the implant, it has got limited bony overgrowth.
An intervertebral spinal implant in a form of a body with a concave side, a convex side and bearing sides provided with at least two projections for penetration within vertebral body's wall is disclosed in US 2008/0140085 A1. The projections are formed by elongated edges which extend in a diverging manner from the concave side of the body towards the convex side of the body.
Installation of known implants requires performance of quite great intervertebral distraction, which stems from sharp, protruding anchoring elements in implants, which hamper introduction of the implant into proper place between vertebral bodies. Anchoring of the implant can cause loss of distraction. After installation of the implant into intervertebral space, because of its anchoring, there is no possibility to perform correction of its seating. Small overall surface of overgrowth holes, or their location on the implant in improper places don't provide required spinal stabilization.